MULTIBLADE IMPELLER

Abstract

The multiblade impeller of the present invention comprises a main plate, a side plate having a suction port at a center thereof, and a large number of blades provided between the main plate and the side plate and extend in the radial direction in an arc form. The main plate and the side plate each have a large number of ridge portions, each extending in the radial direction in an arc form so as to coincide with the shape of the blade extending in the radial direction in an arc form. End portions of the blades are inserted in grooves formed inside the ridge portions of the main plate and the side plate and are fixed to the ridge portions by being bent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a multiblade impeller in accordance with a first embodiment of the present invention;

FIG. 2 is an enlarged sectional view of a fixing portion between a main plate/side plate and a blade of the first embodiment;

FIG. 3 is a sectional view of a part, showing a shape of a blade of the first embodiment;

FIG. 4 is a perspective view of a multiblade impeller in accordance with a second embodiment of the present invention;

FIG. 5 is an enlarged sectional view of a fixing portion between a main plate/side plate and a blade of the second embodiment;

FIG. 6 is a sectional view of a part, showing a shape of a blade of a multiblade impeller in accordance with a third embodiment of the present invention;

FIG. 7 is a sectional view of a part, showing the shape of a blade of a multiblade impeller in accordance with a fourth embodiment of the present invention;

FIG. 8 is a sectional view taken along the line VIII-VIII in FIG. 7;

FIG. 9 is a sectional view of a part, showing the shape of a blade of a multiblade impeller in accordance with a fifth embodiment of the present invention;

FIG. 10 is a perspective view of a hub of a multiblade impeller in accordance with a sixth embodiment of the present invention;

FIG. 11 is a sectional view taken along the line XI-XI in FIG. 10; and

FIG. 12 is an enlarged view of portion A in FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will now be described with reference to the accompanying drawings. The same reference numerals in the drawings of the embodiments denote the same or equivalent elements.

A multiblade impeller in accordance with a first embodiment of the present invention is described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view of a multiblade impeller 10 in accordance with the first embodiment of the present invention, FIG. 2 is an enlarged sectional view of a fixing portion between a main plate/side plate and a blade of the first embodiment, and FIG. 3 is a sectional view of a part, showing the shape of the blade of the first embodiment. The multiblade impeller 10 in this first embodiment is an example of multiblade impeller used for a turbofan.

The multiblade impeller 10 comprises a main plate 1, a side plate 2 having a suction port 2c at a center thereof, a large number of blades 3 that are provided between the main plate 1 and the side plate 2 and extend in the radial direction in an arc form, and a hub 4 attached to a central part of the main plate 1. By the rotation of the multiblade impeller 10, air is sucked from the suction port 2c of the side plate 2, and is blown out of an outer periphery of the blade 3.

The main plate 1 has a plurality of ridge portions 1a each extending in the radial direction in an arc form so as to coincide with the shape of the blade 3 extending in the radial direction in an arc form, and the number of ridge portions 1a is equal to the number of blades 3. The side plate 2 has a plurality of ridge portions 2a each extending in the radial direction in an arc form so as to coincide with the shape of the blade 3 extending in the radial direction in an arc form, and the number of ridge portions 2a is equal to the number of blades 3.

End portions 3a of the blade 3 are inserted in grooves 1b and 2b formed inside the ridge portions 1a and 2a of the main plate 1 and the side plate 2, respectively, and are fixed to the ridge portions 1a and 2a by being bent. According to this configuration, since the end portion 3a of the blade 3 is fixed to the ridge portion 1a, 2a having higher strength, high fixing strength can be obtained even if the thicknesses of the main plate 1, the side plate 2 and the blades 3 are decreased, so that the multiblade impeller 10 can be made low in cost, light in weight, and moreover high in reliability. Also, since the rigidity of the main plate 1 and the side plate 2 is increased by the ridge portions 1a and 2a thereof, the thicknesses of the main plate 1 and the side plate 2 can be decreased, so that the weight of the multiblade impeller 10 can be reduced. Thereby, it is possible to facilitate the start and stop of the multiblade impeller 10 and hence to improve the performance of a product in which the multiblade impeller is used, and further it is possible to improve the reliability of the product in which the multiblade impeller is used by decreasing a load to be applied to a driving system of the multiblade impeller. In the case where the rotational speed of the multiblade impeller 10 is controlled by an inverter, the response of rotational speed control is improved, and hence the performance of the product in which the multiblade impeller is used can be improved.

In this embodiment, the end portions 3a of the blades 3 are fixed in the ridge portions 1a, 2a of the main plate 1 and the side plate 2 by being inserted in the grooves 1b, 2b in a state in which the ridge portions 1a, 2a are formed in a vertical state by press forming and by being bent together with the ridge portions 1a, 2a of the main plate 1 and the side plate 2. By this configuration, a far higher fixing strength between the main plate 1/side plate 2 and the blade 3 can be achieved.

Next, the multiblade impeller 10 in accordance with a second embodiment of the present invention is described with reference to FIGS. 4 and 5. FIG. 4 is a perspective view of the multiblade impeller 10 in accordance with the second embodiment of the present invention, and FIG. 5 is an enlarged sectional view of a fixing portion between the main plate/side plate and the blade of the second embodiment. The configuration of the multiblade impeller 10 of this embodiment is basically the same as that of the multiblade impeller 10 of the first embodiment except the point described below, so that the duplicated explanation is omitted.

In the second embodiment, the ridge portions 1a and 2a of the main plate 1 and the side plate 2 have a plurality of locking holes 2d that are positioned at top portions of the main plate 1 and the side plate 2 and are provided in the radial direction. The end portions 3a of the blades 3 have a plurality of locking projecting pieces 3b that pass through the locking holes 2d and are bent, and are fixed to the ridge portions 1a, 2a in contact with the locking holes 2d and inlet side of the grooves 2b. By this configuration, high fixing strength and high rigidity can be obtained by simple work of bending the locking projecting pieces 3b even if the thicknesses of the main plate 1, the side plate 2 and the blades 3 are decreased. Therefore, an advantage that the multiblade impeller 10 can be made low in cost, light in weight, and moreover high in reliability can be achieved, which advantage is the same as that of the first embodiment.

Also, in the second embodiment, gaps are provided between tip end portions of the locking projecting pieces 3b provided at the end portions 3a of the blades 3 and the main plate 1/the side plate 2. Thereby, when the multiblade impeller 10 is rotated, the occurrence of noise, vibrations, and damage caused by the contact between the locking projecting pieces 3b and the main plate 1/the side plate 2 can be prevented.

Further, in the second embodiment, the locking projecting pieces 3b at the end portions 3a of the blades 3 that are caused to pass through the locking holes 2d in the ridge portions 1a, 2a are bent in the direction opposite to each other. Thereby, a far higher fixing strength between the main plate 1/side plate 2 and the blade 3 can be achieved.

Next, third to sixth embodiments of the present invention are described with reference to FIGS. 6 to 12. FIG. 6 is a sectional view of a part, showing the shape of the blade of the multiblade impeller in accordance with the third embodiment of the present invention, FIG. 7 is a sectional view of a part, showing the shape of the blade of the multiblade impeller in accordance with the fourth embodiment of the present invention, FIG. 8 is a sectional view taken along the line VIII-VIII in FIG. 7, FIG. 9 is a sectional view of a part, showing the shape of the blade of the multiblade impeller in accordance with the fifth embodiment of the present invention, FIG. 10 is a perspective view of the hub of the multiblade impeller in accordance with the sixth embodiment of the present invention, FIG. 11 is a sectional view taken along the line XI-XI in FIG. 10, and FIG. 12 is an enlarged view of portion A in FIG. 11. The configurations of the multiblade impellers 10 of the third to sixth embodiments are basically the same as that of the multiblade impeller 10 of the first embodiment or the corresponding embodiment except the points described below.

In the third embodiment, to enhance the rigidity of the blade 3, the blade shape on the inside diameter side of the blade 3 is made an end face 3c obtained by connecting a position of the groove of the main plate 1 to a position of the groove of the side plate 2 by a straight line.

In the fourth embodiment, to enhance the rigidity of the blade 3, a reinforcing rib 5 is formed at a place at which the blade shape overhangs farthest from the straight line connecting the groove position of the main plate 1 to the groove position of the side plate 2 on the inner diameter side of the blade 3.

In the fifth embodiment, to further enhance the rigidity of the blade 3, the reinforcing ribs 5 are formed in the longitudinal and transverse directions of the blade 3.

In the sixth embodiment, as shown in FIG. 10, caulking convex parts 6 are provided on the hub 4, the caulking convex parts 6 are press fitted in slits 1c formed in the main plate 1, and the caulking convex parts 6 are crushed as shown in FIGS. 11 and 12. Thereby, a strong joining between the main plate 1 and the hub 4 can be obtained.

It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims.

Claims

1. A multiblade impeller comprising a main plate, a side plate having a suction port at a center thereof, and a large number of blades that are provided between the main plate and the side plate and extend in a radial direction in an arc form, wherein the main plate and the side plate each has a large number of ridge portions extending in the radial direction in an arc form so as to coincide with the shape of the blade extending in the radial direction in an arc form; andend portions of the blade are inserted in grooves formed inside the ridge portions of the main plate and the side plate, and are fixed to the ridge portions by being bent.

2. The multiblade impeller according to claim 1, wherein the end portions of the blade are fixed in the ridge portions of the main plate and the side plate by being bent together with the ridge portions.

3. The multiblade impeller according to claim 1, wherein the ridge portions of the main plate and the side plate have a plurality of locking holes positioned at top portions thereof and provided in the radial direction, and the end portions of the blades have a plurality of locking projecting pieces that pass through the locking holes and are bent, and is fixed to the ridge portions in contact with the locking holes and inlet sides of the grooves.

4. The multiblade impeller according to claim 3, wherein gaps are provided between tip end portions of the locking projecting pieces provided at the end portions of the blades and the main plate/the side plate.

5. The multiblade impeller according to claim 3, wherein the plurality of locking projecting pieces at the end portions of the blades that are caused to pass through the locking holes in the ridge portions are bent in the direction opposite to each other.

6. The multiblade impeller according to claim 1, wherein shapes on an inner diameter side of the blades are made straight lines connecting positions of the grooves of the main plate to positions of the grooves of the side plate.

7. The multiblade impeller according to claim 1, wherein a reinforcing rib is formed at a place at which the blade shape overhangs farthest from a straight line connecting a position of the groove of the main plate to a position of the groove of the side plate on the inside diameter side of the blade.

8. The multiblade impeller according to claim 1, wherein reinforcing ribs are formed in longitudinal and transverse directions of the blade.

9. The multiblade impeller according to claim 1, wherein a hub is provided at a central portion of the main plate, caulking convex portions are provided in the hub, slits are provided in the main plate, the main plate is press fitted into the caulking convex portions of the hub and the caulking convex portions are crushed so that the hub and the main part is joined.